reorder & document parameters

2 files changed, 45 insertions, 21 deletions

diff --git a/full_model.scad b/full_model.scad
index 22621f6..fa34e79 100644
--- a/full_model.scad
+++ b/full_model.scad
@@ -47,8 +47,8 @@ translate([bar_thickness/2 + x*tray_width, 0, y*tray_height]) {
     rail();
 
     // backplane (to be inserted into the back connector)
-    translate([bar_thickness + backplane_hoffset, hdd_length - hdd_standout,
-               bar_thickness + backplane_voffset])
+    translate([backplane_hoffset, hdd_length - hdd_standout,
+               backplane_voffset])
       backplane_populated();
   }
 }
diff --git a/parameters.scad b/parameters.scad
index 388be89..3af2af7 100644
--- a/parameters.scad
+++ b/parameters.scad
@@ -1,7 +1,12 @@
+/// ARRAY SIZE
+
 // size of the array
 num_hdd_x = 4;
 num_hdd_y = 5;
 
+
+/// PRIMARY DIMENSIONS
+
 // space above hdd available for air flow
 cooling_height = 10;
 
@@ -11,46 +16,65 @@ bar_thickness = 10;
 // length hdd is standing out to be grabbed
 hdd_standout = 25;
 
-// dimensions of the backplane PCB
-backplane_width  = 70;
-backplane_height = 30;
-backplane_thickness = 1.6;
 
-// offsets of the backplane relative to the hdd
-backplane_hoffset = -(bar_thickness - 2);
-backplane_voffset = -(bar_thickness - 2);
-
-// display only: dimensions and offsets of the SATA connector relative
-// to the backplane
-backplane_con_width = 45;
-backplane_con_height = 5;
-backplane_con_depth = 10;
-backplane_con_hoffset = 5 - backplane_hoffset;
-backplane_con_voffset = 15;
+/// METAL PARTS: SCREWS AND RAILS
 
 // outer diameter of thread rod and nut used for support
 rod_diameter = 4;
 nut_diameter = 6;
 nut_height = 3;
 
+// dimensions of the L-shaped rail between front and back
+rail_width = 15;
+rail_height = rail_width;
+rail_thickness = 1;
+
+
+/// HDD SIZE (from spec)
+
 // dimensions of HDDs; not model-specific
 hdd_width = 101.6;
 hdd_height = 25.4;
 hdd_length = 146;
 
-// dimensions of the L-shaped rail between front and back
-rail_width = 15;
-rail_height = rail_width;
-rail_thickness = 1;
+
+/// PRINTER SPECIFICATION
 
 // assumed space deviation of the resulting form; used to leave space
 // in holes so that screws and rods do not stuck
 pla_epsilon = 0.1;
 
+
+/// COMPUTED VARIABLES
+
 // dimension of a single hdd tray (hdd + space around)
 tray_height = hdd_height + max(cooling_height, 2 * bar_thickness + 10 * pla_epsilon);
 tray_width = hdd_width + bar_thickness;
 
+
+/// PCB DIMENSIONS
+
+// free space around backplanes
+backplane_margin = 1;
+
+// dimensions of the backplane PCB
+backplane_width  = tray_width / 2 + 2 * bar_thickness;
+backplane_height = tray_height - 2 * backplane_margin;
+backplane_thickness = 1.6;
+
+// offsets of the backplane relative to the hdd
+backplane_hoffset = -backplane_margin - bar_thickness/2;
+backplane_voffset =  backplane_margin;
+
+// display only: dimensions and offsets of the SATA connector relative
+// to the backplane
+backplane_con_width = 45;
+backplane_con_height = 5;
+backplane_con_depth = 10;
+backplane_con_hoffset = 5 - backplane_hoffset;
+backplane_con_voffset = 15;
+
+
 /// OPENSCAD HACKS
 
 // a length larger than any constructed feature; use to simulate